Japanese Patent Laid-Open Publication No. HEI-5-201294, for example, discloses a method for diagnosing faults in such vehicle systems using a fault diagnostic device. Such a fault diagnostic system is schematically shown in FIG. 9 hereof.
In the system of FIG. 9, diagnosis of faults in an engine control system 212, anti-lock braking system 213, electric power steering system 214 and certain other system 215 is performed by a fault diagnostic device 201 connected to the systems 212-215 to read the results of self-diagnosis done by the systems 212-215 as self-diagnostic data.
The fault diagnostic device 201 consists of a main unit 202 for directly accessing the systems of the vehicle to read self-diagnostic data of faults or the like, a cord 203 extending from the main unit 202, and a connector terminal 204 attached to the distal end of the cord 203. Reference numeral 205 denotes a display for providing self-diagnostic data, and 206 operation keys for accessing the systems 212 to 215.
In the figure, reference numeral 200 denotes a vehicle, and 208 a plug to which the connector terminal 204 of the fault diagnostic device 201 is connected to read the self-diagnostic data of the systems 212-215.
In the above fault diagnostic operation, however, to perform fault diagnosis of the engine control system 212, anti-lock braking system 213, electric power steering system 214 and the like, it is required to provide the fault diagnostic device 201 and connect the connector terminal 204 of the fault diagnostic device 201 to the plug 208 for fault diagnosis of the systems 212-215. In short, the fault diagnostic operation of the systems 212-215 is complicated and time-consuming.
Further, the above fault diagnostic operation cannot be performed without the fault diagnostic device 201, and is unsuitable for emergent fault diagnostic operation on a street or in parking.
It is thus desired to be able to swiftly proceed with fault diagnostic operation and to perform the operation also on a street or in parking.